Electromagnetic interference (EMI) is a common problem faced during the operation of electronic equipment. EMI is unwanted electromagnetic energy entering or emitting from a piece of electronic equipment, thereby causing interference. EMI can cause that piece of electronic equipment or electronic equipment nearby to function improperly or to not function at all.
Electronic equipment can be housed within a metallic enclosure to help reduce EMI problems. Metallic materials are electrically conductive which serve to block EMI. However, joints or other openings in the enclosure or at cable connection points tend to provide a source of radiation leakage that can cause a reduction in shielding effectiveness.